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-rw-r--r--auth-krb5.c259
1 files changed, 259 insertions, 0 deletions
diff --git a/auth-krb5.c b/auth-krb5.c
new file mode 100644
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1/*
2 * Kerberos v5 authentication and ticket-passing routines.
3 *
4 * $FreeBSD: src/crypto/openssh/auth-krb5.c,v 1.6 2001/02/13 16:58:04 assar Exp $
5 * $OpenBSD: auth-krb5.c,v 1.1 2001/06/26 16:15:23 dugsong Exp $
6 */
7
8#include "includes.h"
9#include "ssh.h"
10#include "ssh1.h"
11#include "packet.h"
12#include "xmalloc.h"
13#include "log.h"
14#include "servconf.h"
15#include "uidswap.h"
16#include "auth.h"
17
18#ifdef KRB5
19#include <krb5.h>
20
21extern ServerOptions options;
22
23static int
24krb5_init(void *context)
25{
26 Authctxt *authctxt = (Authctxt *)context;
27 krb5_error_code problem;
28 static int cleanup_registered = 0;
29
30 if (authctxt->krb5_ctx == NULL) {
31 problem = krb5_init_context(&authctxt->krb5_ctx);
32 if (problem)
33 return (problem);
34 krb5_init_ets(authctxt->krb5_ctx);
35 }
36 if (!cleanup_registered) {
37 fatal_add_cleanup(krb5_cleanup_proc, authctxt);
38 cleanup_registered = 1;
39 }
40 return (0);
41}
42
43/*
44 * Try krb5 authentication. server_user is passed for logging purposes
45 * only, in auth is received ticket, in client is returned principal
46 * from the ticket
47 */
48int
49auth_krb5(Authctxt *authctxt, krb5_data *auth, char **client)
50{
51 krb5_error_code problem;
52 krb5_principal server;
53 krb5_data reply;
54 krb5_ticket *ticket;
55 int fd;
56
57 server = NULL;
58 ticket = NULL;
59 reply.length = 0;
60
61 problem = krb5_init(authctxt);
62 if (problem)
63 goto err;
64
65 problem = krb5_auth_con_init(authctxt->krb5_ctx,
66 &authctxt->krb5_auth_ctx);
67 if (problem)
68 goto err;
69
70 fd = packet_get_connection_in();
71 problem = krb5_auth_con_setaddrs_from_fd(authctxt->krb5_ctx,
72 authctxt->krb5_auth_ctx, &fd);
73 if (problem)
74 goto err;
75
76 problem = krb5_sname_to_principal(authctxt->krb5_ctx, NULL, NULL ,
77 KRB5_NT_SRV_HST, &server);
78 if (problem)
79 goto err;
80
81 problem = krb5_rd_req(authctxt->krb5_ctx, &authctxt->krb5_auth_ctx,
82 auth, server, NULL, NULL, &ticket);
83 if (problem)
84 goto err;
85
86 problem = krb5_copy_principal(authctxt->krb5_ctx, ticket->client,
87 &authctxt->krb5_user);
88 if (problem)
89 goto err;
90
91 /* if client wants mutual auth */
92 problem = krb5_mk_rep(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
93 &reply);
94 if (problem)
95 goto err;
96
97 /* Check .k5login authorization now. */
98 if (!krb5_kuserok(authctxt->krb5_ctx, authctxt->krb5_user,
99 authctxt->pw->pw_name))
100 goto err;
101
102 if (client)
103 krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
104 client);
105
106 packet_start(SSH_SMSG_AUTH_KERBEROS_RESPONSE);
107 packet_put_string((char *) reply.data, reply.length);
108 packet_send();
109 packet_write_wait();
110
111 err:
112 if (server)
113 krb5_free_principal(authctxt->krb5_ctx, server);
114 if (ticket)
115 krb5_free_ticket(authctxt->krb5_ctx, ticket);
116 if (reply.length)
117 xfree(reply.data);
118
119 if (problem) {
120 debug("Kerberos v5 authentication failed: %s",
121 krb5_get_err_text(authctxt->krb5_ctx, problem));
122 return (0);
123 }
124 return (1);
125}
126
127int
128auth_krb5_tgt(Authctxt *authctxt, krb5_data *tgt)
129{
130 krb5_error_code problem;
131 krb5_ccache ccache = NULL;
132 char *pname;
133
134 if (authctxt->pw == NULL || authctxt->krb5_user == NULL)
135 return (0);
136
137 temporarily_use_uid(authctxt->pw);
138
139 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_fcc_ops, &ccache);
140 if (problem)
141 goto fail;
142
143 problem = krb5_cc_initialize(authctxt->krb5_ctx, ccache,
144 authctxt->krb5_user);
145 if (problem)
146 goto fail;
147
148 problem = krb5_rd_cred2(authctxt->krb5_ctx, authctxt->krb5_auth_ctx,
149 ccache, tgt);
150 if (problem)
151 goto fail;
152
153 authctxt->krb5_fwd_ccache = ccache;
154 ccache = NULL;
155
156 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
157
158 problem = krb5_unparse_name(authctxt->krb5_ctx, authctxt->krb5_user,
159 &pname);
160 if (problem)
161 goto fail;
162
163 debug("Kerberos v5 TGT accepted (%s)", pname);
164
165 restore_uid();
166
167 return (1);
168
169 fail:
170 if (problem)
171 debug("Kerberos v5 TGT passing failed: %s",
172 krb5_get_err_text(authctxt->krb5_ctx, problem));
173 if (ccache)
174 krb5_cc_destroy(authctxt->krb5_ctx, ccache);
175
176 restore_uid();
177
178 return (0);
179}
180
181int
182auth_krb5_password(Authctxt *authctxt, const char *password)
183{
184 krb5_error_code problem;
185
186 if (authctxt->pw == NULL)
187 return (0);
188
189 temporarily_use_uid(authctxt->pw);
190
191 problem = krb5_init(authctxt);
192 if (problem)
193 goto out;
194
195 problem = krb5_parse_name(authctxt->krb5_ctx, authctxt->pw->pw_name,
196 &authctxt->krb5_user);
197 if (problem)
198 goto out;
199
200 problem = krb5_cc_gen_new(authctxt->krb5_ctx, &krb5_mcc_ops,
201 &authctxt->krb5_fwd_ccache);
202 if (problem)
203 goto out;
204
205 problem = krb5_cc_initialize(authctxt->krb5_ctx,
206 authctxt->krb5_fwd_ccache, authctxt->krb5_user);
207 if (problem)
208 goto out;
209
210 problem = krb5_verify_user(authctxt->krb5_ctx, authctxt->krb5_user,
211 authctxt->krb5_fwd_ccache, password, 1, NULL);
212 if (problem)
213 goto out;
214
215 authctxt->krb5_ticket_file = (char *)krb5_cc_get_name(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
216
217 out:
218 restore_uid();
219
220 if (problem) {
221 debug("Kerberos password authentication failed: %s",
222 krb5_get_err_text(authctxt->krb5_ctx, problem));
223
224 krb5_cleanup_proc(authctxt);
225
226 if (options.kerberos_or_local_passwd)
227 return (-1);
228 else
229 return (0);
230 }
231 return (1);
232}
233
234void
235krb5_cleanup_proc(void *context)
236{
237 Authctxt *authctxt = (Authctxt *)context;
238
239 debug("krb5_cleanup_proc called");
240 if (authctxt->krb5_fwd_ccache) {
241 krb5_cc_destroy(authctxt->krb5_ctx, authctxt->krb5_fwd_ccache);
242 authctxt->krb5_fwd_ccache = NULL;
243 }
244 if (authctxt->krb5_user) {
245 krb5_free_principal(authctxt->krb5_ctx, authctxt->krb5_user);
246 authctxt->krb5_user = NULL;
247 }
248 if (authctxt->krb5_auth_ctx) {
249 krb5_auth_con_free(authctxt->krb5_ctx,
250 authctxt->krb5_auth_ctx);
251 authctxt->krb5_auth_ctx = NULL;
252 }
253 if (authctxt->krb5_ctx) {
254 krb5_free_context(authctxt->krb5_ctx);
255 authctxt->krb5_ctx = NULL;
256 }
257}
258
259#endif /* KRB5 */